What is an immortals' artifact?
In the eyes of humans, anything that is incomprehensible yet possesses unique functions can be called an immortals' artifact.
However, many modern people feel that the name is somewhat ignorant, and thus they begin to refer to some dazzling things as products of a high civilization.
Change the name, and it seems much more scientific and sober, but what about the essence? It appears to be no different.
Of course, there are also those who maintain their naivety, convinced that immortals' artifacts truly exist and must be refined into being. As for the logic behind refinement, it's fine to attribute it to the ancient gods and immortals.
From this slightly amusing phenomenon, it would seem that ancient technology could be far superior to modern technology. Otherwise, how could the ancients create so many things that modern people do not understand?